Field of the Invention: Embodiments of the invention relate to the production of hydrogen (H2) and carbon monoxide (CO) and in particular to the production of hydrogen and carbon monoxide from water or steam and carbon dioxide; the hydrogen and carbon monoxide may be used in fuel production.
State of the Art: Energy consumption in the United States and throughout the world continues to increase. As the demands for energy increase, additional methods for producing energy are developed. Concerns about the increased wastes and pollutants produced by many of the conventional energy production processes, and the low efficiencies of such processes, have led to further research for cleaner, safer, and more readily available energy sources.
In response to the increasing energy production requirements and the desire to reduce or eliminate pollutants from energy sources, new, cleaner, fuel sources are being sought. A known source of cleaner fuels includes synthetic fuels, or synfuels, made from synthesis gas, or syngas. The conversion of syngas into synfuels, using processes such as the Fischer-Tropsch process, is known and has been used throughout the world. In recent times, with the sustained prices for oil reaching over fifty dollars per barrel, the conversion of syngas into synfuels provides a viable economic alternative to the continued use of naturally occurring sources of oil and fuels produced from such sources. Further, synfuels may burn cleaner than natural oil and fuels produced therefrom.
Syngas comprises carbon monoxide (CO) and hydrogen (H2). Syngas may be converted or refined to form synfuels such as methane. For example, carbon monoxide and hydrogen may be catalyzed in a Fischer-Tropsch process to convert the carbon monoxide and hydrogen into liquid hydrocarbons. The synfuels produced from the syngas may include high purity fuels having fewer pollutants than naturally occurring fuels or fuels processed from naturally occurring oil deposits.
The production of syngas is required for the production of synfuels. As the economic viability of producing synfuels from syngas improves, new sources of syngas and methods for producing syngas have been developed.
High temperature solid-oxide fuel cells may be used to produce electricity and water from hydrogen and oxygen. When run in reverse, the solid-oxide fuel cells act as solid-oxide electrolysis cells, which are able to electrolytically reduce and split water into hydrogen and oxygen. Thus, water may be converted into hydrogen, which may be combined with carbon monoxide to form a syngas. In a solid-oxide fuel cell the anode is the reducing gas electrode and the cathode is the oxidant-side electrode. When operated in reverse, as a solid-oxide electrolysis cell, the anode is the oxidant-side electrode and the cathode is the reducing electrode.
In some recent studies, it has been suggested that solid-oxide electrolysis cells may be used for high temperature electrolysis of water and carbon dioxide into hydrogen and carbon monoxide. Therefore, it would be beneficial to develop systems and methods for converting water and carbon dioxide into hydrogen and carbon monoxide for use in syngas and synfuels production processes.